Right now, I do the GS workouts on alternating days with cardio, abs and Butts and Gutts. Like this:
Day 1: GS Legs
Day 2: Cardio and Abs
Day 3: GS Back Shoulder Biceps
Day 4: Cardio and Abs
Day 5: Butts AND Gutts (extra ab work)
Day 6: Cardio and Abs
Day 7: GS Chest Triceps
Day 8: Rest (or something light and quick, like stretching)
Since there are 7 days in a week and my schedule runs 8 days, it means I'm not always dreading That Workout That Always Falls On Monday but I do it this way so I can have a more balanced routine and cover all my bases. In my routine, I get full upper body once a week and 2 lower body workouts (because that's where I need it most). Because all the science indicates that overweight people (me... still) should emphasize weight training (to build muscle because the more muscle you have the more fat you burn) for a long time I ignored cardio. I reintroduced it when I got tired of being winded during fast-paced weight training sessions.
If time permits, I sometimes throw in some miscellaneous workout (Usually not Cathe... something from my extensive collection of dvd workouts or a walk in the park or pilates) when I can.